What Is Adder Board? And Why Do I Need It?

So you’ve just received an estimate for new gutters and there’s a line item that says adder board that seems to be pricey and has driven up the overall bottom line total. You’ve even gotten other estimates from competing companies and no-one except Alo Seamless Gutters has included adder baord. Is this some kind of way to just get more money you ask? And why is Alo Seamless the only one who has suggested this item? Well, read on.
Let me first start by saying that Alo Seamless Gutters is all about quality, functionality, and longevity of gutter systems. We often add items that others overlook or decide not to include as their way of trying to get a low bottom line and just book a job. This kind of attitude does not serve the best interests of the customers and is not something we ever practice. We will even tell our customers upfront that if you’re shopping strictly by price, then don’t waste your time or ours by asking us for a quote. With gutter systems, like everything else in life, you get what you pay for. Simply put, if you are looking for the best in quality and materials to ensure the job is done right the first time, then we are your company. This is one reason that our estimates are a little different, because we do care and we do want to get it right the first time. But enough about that, you can read our other blogs which touch on this subject as well. So what is adder board and why did we suggest it?
Fascias come in all shapes and sizes. The picture below shows a new home with wide shadowboards and short fascias as a result (the shadowboard is the stepped out trim piece along the top of the fascia surface which usually supports a drip edge, the fascia is the flat surface below).

New Home with Wide Shadowboard and Short Fascia

New Home with Wide Shadowboard and Short Fascia


As you can see, the mounting surface for the gutters are stepped and not a single plane. An adder board, be it either primed and painted wood or PVC, is cut to fit the width of the fascia under the shadowboard to “flesh it out” so that there is one solid flat plane, resulting in full support for the gutters all down the backside. The picture below here shows a close-up of the area with a PVC adder board installed (prior to the gutters going up).
New PVC Adder Board Installed on Fascia

New PVC Adder Board Installed on Fascia


As you can see, the small piece (or adder) flushes out the fascia surface as one complete flat plane. Because the fascia is small to begin with and the shadowboard wide, if we were to hang the gutters from the shadowboard, they’d tilt forward over time with winter ice and snow loads because there’s no support on the bottom of the backside. If we were to hang the gutters from the narrow fascia, with pitch towards a downspout, by the time the gutter gets to the downspout spot, it is either hanging well below the fascia (again, no backside support and it looks ugly) or pitched off the fascia entirely. It is also set back an additional 3/4″ of an inch, lessening the “catch area” of the gutter. The adder piece allows us to use the whole width of the area under the shingle overhangs so we can get proper gutter pitch, the gutter is out far enough to provide adequate catch (important during times of torrential rains- not enough catch means overshooting), as well as providing solid support along the complete backside of the gutter. Here’s another perspective on the fascia with the adder board installed:
Perspective Showing Adder Board Making Flat Wide Surface To Mount New Gutters To

Perspective Showing Adder Board Making Flat Wide Surface To Mount New Gutters To


Most gutter companies just want your money, and they will hang their product either from the shadowboard, or use the fascia, with little or not pitch or pitched improperly or hanging well below the fascia boards at the downspouts. This is really not any kind of proper way to mount a gutter, and the companies that omit these details and considerations are NOT looking out for your best interests. An improperly mounted and/or supported gutter will cause nothing but issues over the long haul. It may look great and function OK for a time, but it will eventually come down on you because it is not supported properly, or it will pour on you because the gutter is too low and too far back from the shingle edges to be of much good use. This is why we add this item to certain jobs, which again are very dependent upon fascia configuration and overhang. It is not an attempt to just get more money, but to do a job right the first time knowing that it will hold up even under the most adverse of conditions. This is looking out for the customers’ best interests, as well as our own – ensuring it’s done right the first and only time.
Any Bozo can sell you gutters and tell you they’ll hang them from your fascias regardless of the configuration. And they probably can and will if allowed. But buyer beware! Shortcuts and low prices may be the quick inexpensive fix, but it will end up costing a lot more in the long run. And with your (probably) biggest investment – your home – on the line, I know I wouldn’t want to take a chance. I’d rather have it done right the first time. And that’s what we are all about. So if you don’t understand why you need adder board, or are unsure about it’s application, I hope the preceding has helped educate you on this matter. And of course, you can always call the us with any questions on any item(s) we propose.
A quick “Hello” to our hard working crew Mike, Alex, and Jon, and of course a big shout-out to our owner/operator Joe Alo. They’ve been busy installing adder board and blocks and new gutters and downspouts and replacing rotted fascias and removing old wooden gutters and the list goes on and on, but they are doing professional quality work as usual and we all really appreciate it. Thanks for the efforts in Concord and Chelmsford recently, and we are looking forward to the big seamless gutter job in Boxborough (with adder board) coming up soon. Keep up the good work guys – you make my job that much easier!

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